NFS can be exported over TCP or UDP. Default transport protocol for NFSv4 is TCP. Whenever we mount the NFS as below, the connection gets established over TCP. If we want to mount NFS over UDP then we have to use -o udp switch as explained below.
NFS over TCP:
mount -t nfs //[ip-address or hostname]
NFS over UDP:
mount -t nfs -o udp //[ip-address or hostname]: